Go patch committed: Remove unsafe.Pointer handling from type assertions

Go patch committed: Remove unsafe.Pointer handling from type assertions

[Ian Lance Taylor]

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The Go frontend had some old code for special handling of unsafe.Pointer
for type assertions.  That is not part of the current language, and
would actually break some otherwise valid programs.  This patch removes
the special handling, and fixes one piece of gccgo-specific code in
libgo that used it.  Bootstrapped and ran Go testsuite on
x86_64-unknown-linux-gnu.  Committed to mainline and 4.7 branch.

Ian


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diff -r 4cd85453373c go/expressions.cc
--- a/go/expressions.cc	Mon Aug 20 22:28:53 2012 -0700
+++ b/go/expressions.cc	Wed Aug 22 17:08:07 2012 -0700
@@ -12914,26 +12914,8 @@
 void
 Type_guard_expression::do_check_types(Gogo*)
 {
-  // 6g permits using a type guard with unsafe.pointer; we are
-  // compatible.
   Type* expr_type = this->expr_->type();
-  if (expr_type->is_unsafe_pointer_type())
-    {
-      if (this->type_->points_to() == NULL
-	  && (this->type_->integer_type() == NULL
-	      || (this->type_->forwarded()
-		  != Type::lookup_integer_type("uintptr"))))
-	this->report_error(_("invalid unsafe.Pointer conversion"));
-    }
-  else if (this->type_->is_unsafe_pointer_type())
-    {
-      if (expr_type->points_to() == NULL
-	  && (expr_type->integer_type() == NULL
-	      || (expr_type->forwarded()
-		  != Type::lookup_integer_type("uintptr"))))
-	this->report_error(_("invalid unsafe.Pointer conversion"));
-    }
-  else if (expr_type->interface_type() == NULL)
+  if (expr_type->interface_type() == NULL)
     {
       if (!expr_type->is_error() && !this->type_->is_error())
 	this->report_error(_("type assertion only valid for interface types"));
@@ -12966,23 +12948,10 @@
 tree
 Type_guard_expression::do_get_tree(Translate_context* context)
 {
-  Gogo* gogo = context->gogo();
   tree expr_tree = this->expr_->get_tree(context);
   if (expr_tree == error_mark_node)
     return error_mark_node;
-  Type* expr_type = this->expr_->type();
-  if ((this->type_->is_unsafe_pointer_type()
-       && (expr_type->points_to() != NULL
-	   || expr_type->integer_type() != NULL))
-      || (expr_type->is_unsafe_pointer_type()
-	  && this->type_->points_to() != NULL))
-    return convert_to_pointer(type_to_tree(this->type_->get_backend(gogo)),
-			      expr_tree);
-  else if (expr_type->is_unsafe_pointer_type()
-	   && this->type_->integer_type() != NULL)
-    return convert_to_integer(type_to_tree(this->type_->get_backend(gogo)),
-			      expr_tree);
-  else if (this->type_->interface_type() != NULL)
+  if (this->type_->interface_type() != NULL)
     return Expression::convert_interface_to_interface(context, this->type_,
 						      this->expr_->type(),
 						      expr_tree, true,
diff -r 4cd85453373c libgo/go/os/dir.go
--- a/libgo/go/os/dir.go	Mon Aug 20 22:28:53 2012 -0700
+++ b/libgo/go/os/dir.go	Wed Aug 22 17:08:07 2012 -0700
@@ -49,7 +49,7 @@
 		file.dirinfo.dir = r
 	}
 
-	entry_dirent := unsafe.Pointer(&file.dirinfo.buf[0]).(*syscall.Dirent)
+	entry_dirent := (*syscall.Dirent)(unsafe.Pointer(&file.dirinfo.buf[0]))
 
 	size := n
 	if size < 0 {